PSD-95 holds your long term memories in place

Image by pchow98 via Flickr One of the cool things about the brain & one of the ways in which it differs markedly from our current computer systems is that cells and synapses are living dynamic entities that grow and sprout new connections in response to experience. Since the 1980’s studies using protein synthesis inhibitors have shown that protein synthesis is necessary for an organism to store, recall and re-store, etc. various aspects of memory. The question for some time has been, “well, what protein(s) exactly ?” In their paper entitled, “ERK-dependent PSD-95 induction in the gustatory cortex is necessary for taste learning, but not retrieval” [DOI:10.1038/nn.2190], Elkobi et al., examine the role of PSD-95 a sort of general purpose scaffolding protein expressed in post-synaptic membranes that anchors the many molecular components that make up the synaptic machinery. They show that PSD-95 is indeed upregulated in the rat gustatory cortex after exposure to a novel stimulus (flavor) and that when it is selectively down-regulated via lentiviral expressed siRNA, that the creation of long term memories was disrupted. Interestingly, the paper shows a 3-hr time lag in the induction of PSD-95 after exposure to the memorable stimulus. Wow, that means I have 3 hours to selectively block long-term memories … I wonder what would be worth not remembering ?